Panoramic photography, the taking of a photograph or photographs covering an elongated field of view, has a long history in photography. Perhaps the most primitive method of panoramic photography is the taking of several adjoining photos with a conventional camera and then mounting the prints together in alignment to achieve a complete panorama. Modem techniques adapt this method by using digital cameras to capture the images, and then using computer image processing techniques to align the images for printing as a single panorama.
The continuous development of digital camera technologies along with constantly increasing speed and processing power of computers have laid the foundation for digital imaging systems that are capable of acquiring image data for the automatic creation of wide to entire 360° panoramas, including both still panoramic images and dynamic panoramic movies.
Currently, main-stream panoramic imaging solutions can be generally categorized into the multi-lens approach and the single-lens approach. Multi-lens panoramic camera systems utilize a set of cameras for simultaneous image or video capturing. The cameras are typically arranged in either a parallel fashion or a converged fashion, such that each camera's field of view overlaps with that of at least one other camera. This way, the total field of view covered by the multi-camera systems is significantly enlarged as compared to a conventional single-lens camera. Hence, during panoramic video capturing, a multi-camera panoramic system generates multiple channels of simultaneous video signals, which are immediately output from the multiple cameras and transmitted to a processor, such as an accelerated processing unit (APU) of the multi-camera panoramic system for post-processing.
Typically, between the multiple output ports of the cameras and the input ports of the processor is a video input interface configured to provide proper matching between the data format of the raw video signals and input data format of the processor. When designing multi-channel video signal interfaces for a multi-camera panoramic system, a designer often has to deal with a limited number of available video input ports on the processor, such as an APU. Typically, an APU has only one or two video input ports. Thus, to accommodate multi-camera panoramic systems which can have for example, 4, 6, 8, 10, 12 or more output signal channels, it is necessary to expand the video input interface to accommodate the multiple channels of video signals. One existing solution to handle more output video channels than the input ports of the APU is by multiplexing. For example, some video decoders from Texas Instruments are designed to multiplex four video channels into a single video channel, thus offering a solution to aforementioned problem of the APU video input port shortage. However, existing systems can only support multiplexing four low-resolution video channels such as 720×576p, 720×480p resolutions into a single video input, but unable to process high-definition video signals at 1280×720p, 1920×1080p or other high resolutions. Unfortunately, there are no available off-the-shelf systems which offer the solution for multiplexing multiple channels of high-definition videos into a single input channel.